Surgical Forceps Capable of Adjusting Seal Plate Width Based on Vessel Size

ABSTRACT

A surgical forceps includes a housing having a shaft attached thereto and an end effector assembly disposed at a distal end of the shaft. The end effector assembly includes first and second jaw members having opposed seal plates, each of the seal plates having a width. At least one of the jaw members is moveable from an open position to a closed position for grasping tissue therebetween. A sensing component is configured to determine an output relating to a diameter of tissue or a composition of tissue disposed between the opposed seal plates of the first and second jaw members. An expanding component is configured to expand the width of at least one of the opposed seal plates according to the determined output.

BACKGROUND

The present disclosure relates to a surgical forceps, and moreparticularly, to a surgical forceps and method for determining andadjusting a seal plate width based upon a diameter of tissue to besealed.

TECHNICAL FIELD

As an alternative to open forceps for use with open surgical procedures,modern surgeons use endoscopic or laparoscopic instruments for remotelyaccessing organs through smaller, puncture-like incisions. Morerecently, Natural Orifice Translumenal Endoscopic Surgery (NOTES)procedures have been developed, for example, to access the abdominalcavity via the mouth, for scar-less surgery. Much like laparoscopy,NOTES is beneficial to patients in that it reduces scarring and healingtime. However, while these minimally invasive surgical procedures areadvantageous in many respects, the reduced access area presents newproblems for surgical instrument design. For example, achieving a highseal pressure with a surgical forceps becomes increasingly moredifficult as the size of the jaw members decrease.

Further, it has been found that the seal pressure required to adequatelyseal a vessel is dependent on both the vessel size and seal plate width.Accurate application of pressure is important to oppose the walls of thevessel, to reduce tissue impedance to a low enough value that allowsenough electrosurgical energy through tissue, to overcome the forces ofexpansion during tissue heating, and to contribute to the end tissuethickness which is an indication of a good seal. If the pressure is notgreat enough, the vessel may not properly or effectively seal and if thepressure is too great, the seal may shred or tear.

Accordingly, instead of attempting to identify and apply a specificpressure to a vessel according to vessel size and seal plate width, apre-determined pressure may be applied to adequately seal different sizevessels if the seal plate widths are adjustable according to thediameter of the vessel to be sealed. Such a feature would also beadvantageous in the design of surgical instruments in that a designerneed not provide an instrument capable of applying a wide-range of sealpressures, but, rather, can provide an instrument capable of applying asingle pre-determined pressure for sealing vessels.

SUMMARY

In accordance with the present disclosure, a surgical forceps isprovided that includes a housing having a shaft attached to the housing.An end effector assembly is attached at a distal end of the shaft. Theend effector assembly includes first and second jaw members havingopposed seal plates, each of the seal plates having a width. One or bothjaw members are moveable from an open position to a closed position forgrasping tissue. A sensing component is configured to determine anoutput relating to a diameter of tissue and/or a composition of tissuedisposed between the opposed seal plates. An expanding component isconfigured to expand the width of one or both seal plates according tothe determined output.

In one embodiment, the sensing component includes a pair of electrodesoperably associated with the jaw members. The electrodes are configuredto measure an electrical characteristic of tissue disposed between thejaw members, thereby determining the diameter of tissue or thecomposition of tissue disposed therebetween. In one embodiment, theelectrical characteristic is impedance.

In another embodiment, a processing component is included. Theprocessing component is configured to convert the output into a sealplate width according to user-input data. The processing component is incommunication with the expanding component such that the expandingcomponent expands the seal plate widths according to the widthdetermined by the processing component.

In yet another embodiment, the expanding component includes a shapememory alloy. The shape memory alloy is configured to expand the widthsof the seal plates when heated. The shape memory alloy is furtherconfigured to allow the seal plates to return to an un-expanded widthwhen cooled.

In yet another embodiment, the expanding component includes anexpandable substrate disposed within each jaw member. A lumen is definedthrough each of the expandable substrates. The lumens are configured forreceiving a fluid therethrough for expanding the expandable substrates.As the expandable substrates expand, the respective seal plate widthsare expanded as well.

In still yet another embodiment, the expanding component includes a gearassembly configured to expand the widths of the seal plates.

In yet another embodiment, the expanding component includes anexpandable scaffold assembly disposed within each jaw member. Each ofthe expandable scaffold assemblies is configured such that uponexpansion, the widths of the seal plates are also expanded.

In still yet another embodiment, one or more handles is provided formoving the jaw members between the open and closed positions. Further,the handle may be configured such that pulling the handle applies apre-determined seal pressure to seal tissue disposed between the jawmembers.

A method of sealing tissue is also provided in accordance with thepresent disclosure. The method includes providing a forceps having apair of jaw members. The jaw members have opposed seal plates and one orboth jaw members is moveable relative to the other from an open to aclosed position for grasping tissue. The method also includes the stepsof determining an output relating to a diameter of tissue and/or acomposition of tissue disposed between the jaw members, adjusting awidth of the opposed seal plates according to the output, and moving jawmembers from the open to the closed position. Moving the jaw membersfrom the open to the closed position applies a seal pressure to sealtissue disposed between the jaw members.

In one embodiment, the widths of the seal plates are adjusted accordingto the output and user-input data.

In another embodiment, moving the jaw members from the open to theclosed position applies a pre-determined seal pressure to seal tissuedisposed between the jaw members.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1 is a top, perspective view of a surgical forceps including ahousing, a handle assembly, a shaft, and an end effector assembly, foruse with the present disclosure;

FIG. 2 is a enlarged, side, perspective view of the end effectorassembly of FIG. 1 having first and second jaw members, wherein thefirst jaw is shown with parts separated;

FIG. 3 is a side, perspective view of the housing of the forceps of FIG.1, with a half of the housing removed;

FIG. 4 is a top view of the second jaw member of FIG. 2;

FIGS. 5A-5B show a top view of one embodiment of the second jaw memberof FIG. 2 in which a seal plate is removed to show the featuresthereinbelow;

FIGS. 6A-6B show a top view of another embodiment of the second jawmember of FIG. 2 in which the seal plate is removed to show the featuresthereinbelow;

FIGS. 7A-7B show a top view of yet another embodiment of the second jawmember of FIG. 2 in which the seal plate is removed to show the featuresthereinbelow;

FIGS. 8A-8B show a top view of still yet another embodiment of thesecond jaw member of FIG. 2 in which the seal plate is removed to showthe features thereinbelow; and

FIG. 9 is a contour plot of the mean burst pressure as a result of sealplate width and vessel size, with a seal pressure of 120 psi.

DETAILED DESCRIPTION

Turning now to FIG. 1, an endoscopic forceps 10 is shown that includes ahousing 20, a handle assembly 30, a rotating assembly 80, a triggerassembly 70 and an end effector assembly 100. Forceps 10 furtherincludes a shaft 12 having a proximal end 14 that mechanically engageshousing 20 and a distal end 16 configured to mechanically engage endeffector assembly 100. Forceps 10 also includes electrosurgical cable310 that connects forceps 10 to a generator (not shown). Cable 310 hassufficient length to extend through shaft 12 in order to provideelectrical energy to at least one of jaw members 110 and 120 of endeffector assembly 100.

With continued reference to FIG. 1, rotating assembly 80 is operablycoupled to housing 20 and is rotatable approximately 180 degrees ineither direction about a longitudinal axis “A” defined through forceps10. The housing 20 includes two halves that house the internal workingcomponents of the forceps 10. Handle assembly 30 includes a moveablehandle 40 and a fixed handle 50. Fixed handle 50 is integrallyassociated with housing 20 and handle 40 is moveable relative to fixedhandle 50.

Referring now to FIG. 2, end effector assembly 100 is configured formechanical attachment at the distal end 16 of shaft 12 of forceps 10.End effector assembly 100 includes opposing jaw members 110 and 120.Handle 40 of forceps 10 (see FIG. 1) ultimately connects to a driveassembly (not shown) which, together, mechanically cooperate to impartmovement of the jaw members 110 and 120 from a first, open positionwherein the jaw members 110 and 120 are disposed in spaced relationrelative to one another, to a second, clamping or closed positionwherein the jaw members 110 and 120 cooperate to grasp tissuetherebetween. Jaw members 110 and 120 also include longitudinal knifechannels 115 defined therein for reciprocation of a knife blade (notshown) therethrough for cutting tissue.

With continued reference to FIG. 2, opposing jaw members 110 and 120 arepivotably connected about pivot 103 via pivot pin 105. Jaw members 110and 120 include electrically conductive sealing plates 112 and 122,respectively, that are dimensioned to securely engage tissue clampedtherebetween. As shown in FIG. 2, seal plate 112 of jaw member 110includes a number of flanges 113 disposed around a perimeter thereof toengage seal plate 112 with expanding component 114. During assembly,flanges 113 of seal plate 112 are engaged, e.g., slip-fit, with notches117 of expanding component 114, retaining seal plate 112 thereon.Alternatively, seal plates 112 and 122 may be secured to jaw members 110and 120, respectively, via any other suitable means. Jaw member 110further includes a jaw cover 116 for housing the components, e.g.,electrodes 118, insulator 119 and expanding component 114, of jaw member110. Jaw member 120 is constructed similarly to jaw member 110,described above.

As shown in FIG. 2, jaw member 110 includes a sensing component, orelectrode pair 118 disposed therethrough. Although not shown in thedrawings, jaw member 120 is constructed similarly to jaw member 110 andincludes an electrode pair that cooperates with electrode pair 118 tomeasure the impedance across tissue disposed between the jaw members 110and 120. Electrode pair 118 of jaw member 110, for example, may beconfigured to transmit a low-voltage alternating-current through tissuedisposed between the jaw members 110 and 120, while the electrode pairdisposed through jaw member 120 may be configured to receive theresulting voltage after the voltage has passed through tissue. It isalso envisioned that this configuration be reversed, e.g., where thetransmitting electrodes are disposed through jaw member 120 and thereceiving electrodes are disposed through jaw member 110. In eitherconfiguration, the impedance across tissue can be measured and used todetermine the diameter of tissue between jaw members 110 and 120.

Alternatively, the impedance across tissue measured by the pairs ofelectrodes can be used to determine the resistivity of tissue. Sincedifferent components of tissue, e.g., muscle cells, fat cells and fluid,have different resistivities, determining the overall resistivity oftissue can help determine the relative composition of tissue. Further, asecond pair of electrodes (not shown) or sensors may be disposed througheach of the jaw members 110 and 120 such that the first set of electrodepairs may be configured to measure the cross-sectional diameter oftissue while the second set of electrode pairs is configured to measurethe resistivity of tissue.

It is also envisioned that any other suitable sensing component may beprovided in cooperation with jaw members 110 and 120 to measure thecross-sectional diameter and/or to determine the composition of tissuedisposed between jaw members 110 and 120. Further, it is envisioned thatthe sensing component could include sensors disposed along the sealingplates 112 and 122 of jaw members 110 and 120, respectively, for sensingthe gap distance between the respective sealing plates 112 and 122. Bydetermining the gap distance between the sealing plates 112 and 122 atdifferent positions along the plates, the size of the vessel graspedtherebetween can be estimated.

Ultimately, the sensing component may be configured to measure anyelectrical or physical characteristic of tissue that may be used todetermine a diameter of tissue or tissue composition. Accordingly, anysensor that may be used to measure an electrical or physicalcharacteristic of tissue may be provided for use with end effectorassembly 100 of forceps 10. Suitable sensors include, but are notlimited to, impedance sensors, proximity sensors, optical sensors,ultrasonic sensors, chemical sensors, and the like.

Referring now to FIG. 3, housing 20 of forceps 10 is shown having a halfof housing 20 removed. A processing component 21, disposed withinhousing 20, is configured to receive the output, e.g., diameter oftissue and/or composition of tissue, from the sensing component 118. Oneor more leads 33, 37 are disposed through the housing 20 and shaft 10 tothe jaw members 110 and 120 to provide feedback to the processingcomponent 21. The processing component 21 converts the output into aseal plate width according to specific characteristics, as determined bythe output, of tissue to be sealed.

The processing component 21 may include electrical circuitry 22configured to convert the output into a seal plate width for adequatelysealing tissue disposed between the jaw members 110 and 120. Electricalcircuitry 22 may be configured to convert the output to a seal platewidth according to specific parameters and/or data. Alternatively,electrical circuitry 22 may communicate with an external source, e.g., agenerator (not shown), for determining the seal plate widthcorresponding to the output. Further, a computer chip (not shown) may beprovided for storing data and communicating with the electricalcircuitry 22 in order to determine the appropriate seal plate width,based upon the output determined by the sensing component 118. Specificdata sets, e.g., the set of seal plate widths required for adequatesealing of vessels having varying diameters, may be used to convert theoutput into a seal plate width. Algorithms can also be used to determinethe seal plate width based upon the specific output determined.Exemplary data, determined by a study of seal plate width as a functionof vessel size, for configuring the processing component 21, will bediscussed in detail below.

With reference now to FIG. 4, once the output has been determined andconverted into a seal plate width, e.g., via processing component 21,the specific seal plate width is communicated to the jaw members 110 and120 such that the expanding component 124 may expand the width of theseal plates 112 and 122 accordingly. In the following, reference will bemade to jaw member 120 alone but it is understood that the followingrelates to both jaw members 110 and 120.

Generally, as shown in FIG. 4, jaw member 120 includes an electricallyconductive seal plate 122 and defines longitudinal knife channel 115therein. As described above, seal plate 122 is engaged with expandablecomponent 124, e.g., with flanges 123 of seal plate 122 slip-fit intonotches 127 of expandable component 124, which is contained within jawcover 126. Expandable component 124 is in communication with processingcomponent 21 of housing 20 (see FIG. 3) such that upon receiving a sealplate width determined by the processing component 21 (as describedabove), expandable component 124 is expanded to thereby expand sealplate 122 in the direction of arrows “B” and “C,” such that thedetermined width of seal plate 122 is achieved. Accordingly, it isenvisioned that seal plate 122 may be configured to have an at-restwidth which is a minimum width required to adequately seal tissue. Thus,seal plate 122 need only expand from the seal plate 122 at-rest positionto reach the seal plate width required to seal tissue disposed betweenjaw members 110 and 120.

Various embodiments of the expandable component 124 in conjunction withjaw member 120 will now be described in detail with reference to FIGS.5A-8B. Jaw member 110 is constructed similarly to jaw member 120 andtherefore, to avoid duplication, will not be described herein.

FIGS. 5A-5B show jaw member 120 wherein sealing plate 122 has beenremoved. As described above, when seal plate 122 is replaced, flanges123 disposed around the perimeter of seal plate 122 engage notches 127of expandable component 124, thereby securing seal plate 122 thereon. Inthe embodiment shown in FIGS. 5A-5B, expandable component 124 is formedat least partially from a shape memory alloy (SMA) 124. The SMA 124 issurrounded by an insulator 124 to prevent heat from passing through tothe SMA 124 and to prevent heat from escaping from the SMA 124. SMAssuitable for forming expandable member 124 include, but are not limitedto, copper-zinc-aluminum-nickel, copper-aluminum-nickel, andnickel-titanium, commonly referred to in the art as Nitinol alloys. TheSMA 124 is configured for two-way shape memory effect. Thus, the SMA 124associated with sealing plate 122 of jaw member 120 remembers twodifferent shapes, a “cold” shape (e.g., an at-rest position) and a “hot”shape (e.g., an expanded position). For purposes herein, M_(f) is thetemperature at which the transition to a martensite phase or stage isfinished during cooling, and A_(s) and A_(f) are the temperatures atwhich the transition from the martensite phase to austenite phase startsand finishes, during heating. A_(s) may be determined by the SMAmaterial and composition and, typically, ranges from about 150° C. toabout 200° C. A_(f) may also be determined by the SMA material andcomposition and/or the loading conditions and, typically, ranges fromabout 2° C. to about 20° C. or hotter.

Expandable member 124 initially may be in an unexpanded position, asshown in FIG. 5A. This unexpanded, or at-rest, position corresponds tothe SMA 124 being in a cold state, that is, the SMA is in a martensitestate (e.g., M_(f), a point below A_(s)). When the processing component21 determines the appropriate seal plate width, a generator (not shown)may be activated to transmit electrosurgical energy through cable 310into jaw member 120 to heat SMA 124. As SMA 124 “heats up,” iteventually reaches an austenite state (e.g., A_(s)) and begins totransition from the “cold” shape to the “hot” shape, which, in turn,causes expandable member 124 to expand. During the austenite phasetransition (e.g., A_(s)→A_(f)), the expandable member 124 continues toexpand until it reaches a threshold or final austenite stage (A_(f)),shown in FIG. 5B. Since sealing plate 122 is engaged with expandingcomponent 124 via flanges 123 and notches 127, respectively, as the SMA124 is transitioned (expanded) from the “cold” to the “hot” shape, thewidth of sealing plate 122 is correspondingly expanded from theunexpanded position of FIG. 5A (corresponding to the “cold” shape of theSMA 124) to the expanded position of FIG. 5B (corresponding to the “hot”shape of the SMA 124). If the SMA 124 is allowed to cool, the SMA 124,as its temperature decreases, will transition from the austenite stageback to the martensite stage such that the SMA 124, and thus the sealplate width, will return to the unexpanded, or at-rest position.

In operation, as can be appreciated, forceps 10 is positioned such thattissue to be sealed is disposed between jaw member 110 and 120. Thesensing components 118 may then be used to determine an output, e.g.,the diameter of tissue and/or composition of tissue disposed through jawmembers 110 and 120. The determined output is then communicated to theprocessing component 21 for determining an appropriate seal plate widthcorresponding to the specific output. Thereafter, an appropriate amountof electrosurgical energy is supplied to expandable member 124, e.g. viaa generator (not shown), such that the SMA 124 transitions from its“cold” to its “hot” state, thereby expanding seal plate 122 during thistransition. Accordingly, the SMA 124 may be heated to a specific pointsuch that seal plate 122 is expanded to the width determined by theprocessing component 21. A pre-determined seal pressure may then beapplied, e.g., by squeezing handle 40 which, in turn, moves the jawmembers 110 and 120 from the open to the closed position, to adequatelyseal tissue disposed between jaw members 110 and 120.

FIGS. 6A-6B illustrate another embodiment of the jaw member 220 whereinthe seal plate 122 has been removed for viewing purposes. Jaw member 220includes an expandable substrate 224 defining a “U”-shaped lumen 225therethrough. Inlet tubes 230 connect lumen 225 of the expandablesubstrate 224 to an source (not shown) for selectively permitting fluid240 to flow through lumen 225. A plurality of notches 227 is disposedaround the perimeter of expandable substrate 224. Notches 227 areconfigured to engage flanges 123 of seal plate 122 for securing the sealplate 122 in place. Knife channel 215 is defined through a centralportion of expandable substrate 224.

FIG. 6A shows the expandable substrate in a contracted, or fluid-lessstate. At this position, expandable substrate 224, and thus seal plate122 have a minimum width. Upon introduction of a fluid 240 through lumen225 of expandable substrate 224, expandable substrate 224 is expanded tothe position shown in FIG. 6B, thereby expanding seal plate 122 which isengaged to expandable substrate 224 via flanges 123 and notches 227,respectively. Fluid 240 may be a heated fluid 240, such that, uponpassage through lumen 225, fluid 240 heats expandable substrate 224,thereby expanding expandable substrate 224. In this configuration, aninsulator 228 is provided to prevent heat transfer between seal plate122 and expandable substrate 224 and vice versa. As can be appreciated,the removal of fluid 240 from lumen 225 allows expandable substrate 224to cool. As expandable substrate 224 cools, it contracts, therebycontracting the seal plate 122. Thus, in operation, fluid 240 may besupplied in varying amounts and/or temperatures to expand the seal platewidth according to the determined output.

Turning now to the embodiment of FIGS. 7A-7B, jaw member 320 includesexpanding component 324 having notches 327 disposed around a perimeterthereof for engagement with flanges 123 of seal plate 122. Gear assembly340 mechanically cooperates with forcing members 345 a and 345 b toexpand and contract expanding component 324. Forcing members 345 a and345 b are disposed on either side of knife channel 315 defined withinexpanding component 324. As shown in FIG. 7A, forcing members 325 are ina contracted, or close, position. Once the sensing component 118 (seeFIG. 2) and processing component 21 (see FIG. 3) cooperate to determinethe appropriate seal plate width for the particular vessel disposedbetween jaw members 110 and 120, gear assembly 340 is activated toadjust the seal plate width accordingly. For example, gear assembly 340,initially disposed in the position shown in FIG. 7A, may be activatedaccording to the determined diameter of tissue to be sealed such thatgear assembly 340 causes forcing members 315 to translate outwardly.Accordingly, expanding component 324, seal plate 122, and knife channel315 are all expanded to the positions shown in FIG. 7B. The positionshown in FIG. 7B may correspond to a specific seal plate width accordingto the specific output determined.

With reference to FIGS. 8A-8B, jaw member 420 is shown having a scaffoldassembly 424 disposed thereon. A plurality of notches 427, disposedaround the perimeter of scaffold assembly 424, is configured to engageflanges 123 of seal plate 122 for securing the seal plate 122 thereon.Knife channel 415 is defined through a central portion of scaffoldassembly 424. Scaffold assembly 424 includes expanding members 430 andlongitudinal bars 440. Longitudinal bars 440 are configured to maintainthe integrity of scaffold assembly 424, while expanding members 430 areconfigured to expand scaffold assembly 424 from the position shown inFIG. 8A to the position shown in FIG. 8B.

In operation, when the determined seal plate width for sealing theparticular size tissue disposed between the jaw member requires thecurrent seal plate width to be expanded, expanding members 430 areexpanded, thereby forcing longitudinal bars 440 into a spaced-apartconfiguration with respect to one another. This expansion of scaffoldassembly 424 similarly causes the expansion of seal plate 122 accordingto the seal plate width desired. When it is determined that the sealplate width needs to be reduced, expanding members 430 are retracted,bringing longitudinal bars 440 into a closer-together position, therebyretracting scaffold assembly 424 and seal plate 122.

The above-described embodiments of the jaw members 110 and 120 allow theseal plate width to be adjusted according to the diameter of tissueand/or composition of tissue to be sealed. Adjusting seal plate widthallows a user to apply a pre-determined seal pressure to vessels ofvarying sizes. Thus, a user will not have to apply an estimated sealpressure, e.g., by selectively squeezing handle 40 to an estimatedposition according to the estimated seal pressure desired. Instead, auser may apply a single, pre-determined seal pressure for a range ofvessel sizes. Similarly, the instrument may be designed for applicationof a single, pre-determined seal pressure, e.g., where the user squeezeshandle 40 through its complete range of motion to achieve thepre-determined seal pressure. In either of the above configurations,adequate and effective seals are ensured because two factors affectingthe quality of a seal, i.e., vessel size and seal pressure, are used todetermine the appropriate seal plate width for sealing tissue accordingto the above-mentioned factors.

Additionally, seal plates 112 and 122 may be expandable to differentwidths. As can be appreciated, it may be desirable for seal plates 112and 122 to be expandable to different widths in order to properly sealtissue according to the specific size, shape, composition, and/or othercharacteristics of tissue to be sealed. Expanding the opposing sealplates 112, 122 to different widths can be achieved, for example, byallowing the processing component 21 to independently expand the sealplates 112, 122. In such an embodiment, the processing component 21,based upon the determined output, or user input data, would activate theexpanding components 114, 124 to independently expand each respectiveseal plate 112, 122 to a specific width. Thus, if the determined outputindicates that seal plates having different widths would be desirable toseal the particular tissue disposed between jaw members 110 and 120,seal plate 112 would be expanded to a first width, while seal plate 122would be expanded to a second, different width. On the other hand, if itis determined that seal plates having the same width would be moredesirable, seal plates 112 and 122 would both be expanded to thespecific width determined. Alternatively, only one of the seal plates112, 122 may be expandable. For example, seal plate 112 may be fixed inposition, while seal plate 122 is expandable. In this configuration,seal plate 122 can be expanded to the width of seal plate 112 such thatthe seal plates 112 and 122 have equal widths, or seal plate 122 may beexpanded such that the seal plates 112 and 122 have different widths.

As mentioned above, specific data or formulae may be input into theprocessing component 21 to determine the appropriate seal plate widthcorresponding to the diameter of the vessel to be sealed and the sealpressure to be applied. Accordingly, a study was conducted to determinehow seal plate width and blood vessel size, under a constant sealpressure, influence the quality of the seal produced, measured throughburst pressure. Burst pressure is the pressure required to open, orburst, a previously sealed vessel by forcing a fluid through the sealedvessel. The range of values tested for seal plate width was about 0.03inches to about 0.08 inches. Vessel diameters ranged from about 2 mm toabout 6 mm. In the study discussed above, the vessels were sealed byapplying a constant seal pressure of 120 psi. FIG. 9, a contour plot ofburst pressure vs. vessel size, shows the results of the study. Dataextrapolated from FIG. 9 and/or algorithms corresponding to the resultsshown in FIG. 9 can be input into processing component 21 fordetermining the appropriate seal plate width as a function of vesselsize (with a constant seal pressure).

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. While several embodiments of the disclosure have been shownin the drawings, it is not intended that the disclosure be limitedthereto, as it is intended that the disclosure be as broad in scope asthe art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

1. A surgical forceps, the forceps comprising: a housing having a shaftattached thereto and an end effector assembly disposed at a distal endthereof, the end effector assembly including: first and second jawmembers having opposed seal plates, each having a width, at least onejaw member moveable from an open position to a closed position forgrasping tissue therebetween; a sensing component configured todetermine an output relating to a diameter of tissue or a composition oftissue disposed between the opposed seal plates of the first and secondjaw members; and an expanding component configured to expand the widthof at least one of the opposed seal plates according to the determinedoutput.
 2. The surgical forceps according to claim 1, wherein thesensing component includes a pair of electrodes operably associated withthe jaw members, the electrodes configured measure at least oneelectrical characteristic of tissue disposed between the jaw members,thereby determining the cross-sectional diameter of tissue or thecomposition of tissue disposed therebetween.
 3. The surgical forcepsaccording to claim 2, wherein the electrical characteristic isimpedance.
 4. The forceps according to claim 1 further comprising aprocessing component that converts the output into a seal plate widthaccording to user-input data, the processing component communicatingwith the expanding component such that the expanding component expandsthe seal plate width according to the width determined by the processingcomponent.
 5. The forceps according to claim 1, wherein the expandingcomponent includes a shape memory alloy, the shape memory alloyconfigured to expand the width of the seal plates when heated andconfigured to allow the seal plates to return to an un-expanded widthwhen cooled.
 6. The forceps according to claim 1, wherein the expandingcomponent includes an expandable substrate disposed within each jawmember, each expandable substrate defining a lumen therethrough forintroduction of a fluid therein for expanding the expandable substrate,thereby expanding the respective widths of the seal plates.
 7. Theforceps according to claim 1, wherein the expanding component includes agear assembly configured to expand a portion of each jaw member toexpand the widths of the seal plates.
 8. The forceps according to claim1, wherein the expanding component includes an expandable scaffoldassembly disposed within each jaw member, each expandable scaffoldassembly configured to expand to expand the widths of the seal plates.9. The forceps according to claim 1, further comprising at least onehandle that moves the jaw members between the open and closed positions.10. The forceps according to claim 9, wherein pulling the at least onehandle applies a pre-determined seal pressure to seal tissue disposedbetween the jaw members.
 11. A method of sealing tissue, the methodcomprising the steps of: providing a forceps including a pair of jawmembers having opposed seal plates, at least one jaw member moveablerelative to the other from an open to a closed position for graspingtissue therebetween; determining an output relative to a diameter oftissue or a composition of tissue disposed between the jaw members;adjusting a width of at least one of the opposed seal plates accordingto the determined output; and moving the at least one jaw member fromthe open to the closed position to apply a seal pressure to seal tissuedisposed between the jaw members.
 12. The method according to claim 11,wherein the width of the at least one seal plate is adjusted accordingto the output and user-input data.
 13. The method according to claim 11,wherein moving the jaw members from the open to the closed positionapplies a pre-determined seal pressure to seal tissue disposed betweenthe jaw members.